As one of the original 28 subway stations in New York City, the Astor Place station features breathtaking tile work and a wide array of decorative plaques. Unfortunately, commuters rushing to and from their destinations do not always have the opportunity to appreciate its architectural and artistic legacy. One frequently overlooked feature can be found outside the turnstiles on the downtown platform of the 6 train. Next time you enter into the station, stop for a brief moment and look for a bricked up doorway with the words “Clinton Hall” carved above it.

What exactly is “Clinton Hall,” and did the place actually exist? While the blocked off corridor might suggest otherwise, Clinton Hall is indeed still standing; it is located at the triangle of Astor Place on East 8th Street and Lafayette Street.

At one point, it lead into the Mercantile Library Of New York (known as Clinton Hall), at 21 Astor Place, which was the former site of the Astor Place Opera House; at its hey day, the library held more than 120,000 volumes and boasted a membership of 12,000 people. Notable figures such as Ralph Waldo Emerson and Mark Twain also held lectures in the institution. Due to its importance at the time, the library had its own entrance to the subway when it was constructed under the Clinton Hall building in 1904.

The Astor Place Opera House also holds some interesting history itself. In 1849, it was the site of a violent riot, which resulted in the death of at least 25 people. According to Forgotten NY, the controversy took place between supporters of American actor Edwin Forrest and patrons of equally notable English actor William Macready, who bickered about which actor could better play major roles of Shakespeare. Although the topic of the debate might sound petty now, the riot was a culmination of long-standing turmoil between residents born in America and “former colonial overlords.”

Following the incident, the Opera house was torn down in 1890. A new, 11-story Clinton Hall was eventually built on the site in 1904 to house the Mercantile Library. Although this building still exists today, the library is no longer in operation – it left Clinton Hall in 1932 and moved to East 47th Street. (You can find the non-profit Centre For Fiction there now.) More recently, the hall was also converted into apartments in 1995.